The twitter thread (and most of the discussion here) is focused on the optical impact of these satellites. As @watersb mentions in a reply[0] these satellites will likely have an impact on radio telescopes. I've found conflicting information on the frequency bands starlink will use, but all of them would put the emission in the 10s of GHz regime, which is in the middle of commonly used bands by current radio telescopes (e.g., the Very Large Array), future expansions of existing telesopes ("Band 1" for the Atacama Large Millimeter Array), and future radio telescopes (High-frequency Square Kilometer array, Next Generation Very Large Array). Surely these are outside of the "protected" radio frequency bands, but they may still affect the measurements made by the sensitive electronics of radio telescopes.
The linked twitter feed notes that 84 satellites would be in the sky at any time. I don't know how colimated their radio transmissions would be, but it's possible more of them would be "visible" in the radio, compared to the optical. So it could be a significant effect on radio astronomy.